This invention relates to an electronic switch and more particularly to an electronic switch assembly, suitable for use with a power accessory especially with a moving body in a vehicle, such as a vehicle door used in a power window device, a sunroof device, a power lock device and the like.
Common to a modern vehicle, is a switch device, wherein the switch is positioned between or connected to a motor and a number of different items. These items include, but are not limited to, a door lock, a power window, a sun roof, and a vehicle alarm.
Power-assisted windows are available on vehicles of this time. The structure providing a power window involves an electronic switch operated by a conveniently mounted button. The button serves to activate an electric motor in order to raise or lower the window as desired.
A type of controller for any item, including a power window regulator provided in a door of a vehicle on the driver""s side, has a manual mode switch and an automatic mode switch provided as a means for operating the controller. Ordinarily, this type of controller has a construction described below.
A relay is provided to control the energization of the motor for moving the window glass upward or downward. When the manual mode switch is turned on, the relay is operated to form a circuit for the energization of the motor. The window glass is moved upward or downward only for the period of time that the manual mode switch is in the xe2x80x9cONxe2x80x9d state, thereby enabling the window glass to be moved to the desired position.
A retention circuit is provided which maintains the operating state of the relay (that is forming the motor energization circuit), once the relay is operated, by turning on the automatic mode switch. This occurs even after the automatic mode switch has been turned off.
An auto-stop circuit is also provided which detects a locked-rotor current which flows through the motor during the energization of the motor based on the maintained state of the relay. When the locked-rotor current is detected, the auto-stop circuit cancels the maintenance of the operating state of the relay that is affected by the retention circuit. Consequently, once the automatic mode switch is turned on, even for a short time, the operating state of the relay is maintained by the retention circuit even after the automatic mode switch has been turned off, thereby continuing the energization of the motor and, hence, the (upward or downward) movement of the window glass.
When the window glass that is moved in this way reaches a limited position (at which it completely closes or opens the window), a locked-rotor current flows through the motor. The auto-stop circuit detects this locked-rotor current and cancels the operation of the relay, thereby automatically stopping the energization of the motor in response to the window glass reaching the limited position.
However, once the locked-rotor current starts flowing through the motor, it decreases as the temperature of the motor winding increases. In some cases, the locked-rotor current becomes lower than a threshold level for detection of the locked-rotor current in the auto-stop circuit. In such an event, the operation maintained by the retention circuit is not cancelled and the energization of the motor continues uncontrollably. Such uncontrolled action results in the risk of the motor abnormally heating as well as the risk of an increase in the rate at which the vehicle battery; serving as the power source of the power window, is consumed.
Durability is a key feature of the power accessories of a vehicle. The window operation is used as an example. In particular, a major problem occurs whenever the power window does not operate. If the power window becomes stuck in a down position, rain can enter the vehicle. Having the interior of a vehicle become wet, is clearly undesirable. If the power window becomes stuck in an up position, safety of a person in the vehicle can be compromised, especially if the door of the vehicle becomes inoperable for any reason.
The manufacturing process for such a reliable switch can be difficult. Clearly, if a switch can be more easily manufactured, while maintaining the same reliability or better reliability, great advantages can be obtained. Accordingly, an improved switch for a power accessory on a vehicle is extremely desirable.
Among the many objectives of this invention is to provide an improved switch assembly for a power accessory on a vehicle.
Another objective of this invention is to provide an improved switch assembly for a power window on a vehicle.
Yet another objective of this invention is to provide an improved switch assembly for a power sunroof on a vehicle.
Still, another objective of this invention is to provide an improved switch assembly for a power lock on a vehicle.
Additionally, an objective of this invention is to provide an improved switch assembly for a key operated accessory on a vehicle.
Also, an objective of this invention is to provide a durable switch assembly for a power accessory on a vehicle.
A further objective of this invention is to provide an easily manufactured switch assembly for a power accessory on a vehicle.
These and other objectives of the invention (which other objectives become clear by consideration of the specification, claims and drawings as a whole) an electronic switch assembly, with at least one switch thereon, the at least one switch being capable of receiving a contact from a rotating cam, in order to control the power accessory.